Republicans bet the House majority on the Trump tax cut.

Republican Vern Buchanan has represented Sarasota, Fla., in the U.S. House of Representatives since 2007. He won reelection in 2016 by 20 points. He’s a wealthy former car dealer who hasn’t lacked campaign funds. Nor did his son James, who ran in Tuesday’s special election to replace a retiring GOP state legislator from the same area. But James’s story turned out differently from his father’s. He lost to Democrat Margaret Good by seven points.

Democratic successes in local elections like Buchanan’s, and in last year’s contests in Virginia and New Jersey, are a reminder that the House majority is in serious jeopardy. Republicans are cheered by the recent uptick in President Trump’s job approval. They are thrilled to have cut the Democratic lead in the generic ballot by about half in little over a month. (As recently as December, Democrats led by 13 points; that advantage is down to 7.) But a seven-point deficit still worries House Republicans, who say the majority is in trouble if Democrats lead by six or more.

Midterm elections are not kind to incumbents. On average, a president’s party loses 25 seats in the off-year. The Republicans have a House majority of 24 — and 23 of those districts voted for Hillary Clinton in 2016. The out-party increases its gains to an average of 36 seats when a president’s approval rating falls below 50 percent. As I write, President Trump’s approval is 42 percent in the RCP average. The fury at Trump has intensified Democratic enthusiasm and liberal confidence. If you doubt me, take a look at Elizabeth Warren’s recent speech to the National Congress of American Indians. It could have been written by Howard Zinn.

What happens to Republicans depends on two groups: white women and whites with college degrees. Both demographics broke for Trump in 2016. He won white women by 10 points and white college grads by 4 points. But these are precisely the voters that have turned against him and the GOP in the eighteen months since Inauguration Day 2017. Democratic victories in Virginia and in Alabama were fueled by their outrage at Trump’s personality, style, and Tweets, and compounded by apathy and disinterest on the part of the president’s white working class base, who had supported him by 39 points. If white women and college graduates continue to be repelled by the president in an off-year election where he is not on the ballot, then the GOP majority is finished. Simple as that.

But Democrats should not celebrate prematurely. Republicans have some arrows in their quivers, including the economy. One senior Republican notes that the 1998 midterm elections, in which the president’s party did better than expected, were preceded by six quarters of economic growth. And right now the economy is humming, with low unemployment, GDP gains, and wage increases. We’ve gone from an economy where workers are in search of employers to one where employers are in search of workers. Millions of positions are unfilled.

Republicans want to tie the strong economy to the tax cut they passed last December. This is the most powerful weapon they have in the coming election, not just because the policy appears to be succeeding, but also because it’s the only major achievement of the 115th Congress. Republicans are keeping track of how many companies have pegged bonuses, raises, or 401(k) perks to the tax cut — the number currently stands at 348. They urge voters to “check their check,” beginning this week, to see the extra take-home pay the cut has given them. And they are telling candidates to highlight the impact on everyday people: Christmas toys purchased, vacations enjoyed, and small businesses expanded as a result of a policy the GOP embraced but every Democrat in Congress voted against.

And the Democrats may be the House Republicans’ greatest advantage. Their leftward drift, torrid embrace of identity politics, and obsession with rebuking if not outright removing Trump may give swing voters pause. So might the Democratic leadership. Chuck Schumer wants to save the jobs of Democratic senators from red states, but the only job Nancy Pelosi is interested in saving is her own. She’s had a terrible few months, from saying that the tax cut will bring “armageddon,” to dismissing the bonuses and benefits as “crumbs,” to voting to shut down the government over illegal immigrants, to sitting on her hands during the State of the Union as the president lauded an eleven-year-old boy who decorates the graves of veterans, to urging her members to vote against the two-year budget agreement after her pointless DACA-thon. Even the Democratic caucus is tiring of Pelosi, who remains the party’s standard-bearer. The numbers of Democrats who voted against her increased from one government funding bill to the next. And Conor Lamb, the candidate for a Pennsylvania House seat who can’t remember calling Israel a terrorist state when he was a Penn undergraduate, says he’d oppose Pelosi as leader. Of course, he’ll probably forget saying that, too.

The latest Cook Political Report puts 18 GOP seats in the “toss-up” category. Opponents of Trump must be hoping that this number will grow. But there’s one last reason not to jump to conclusions about the 2018 midterm elections. I’m referring to the unprecedented and frankly loopy political environment in which we have found ourselves for the last few years. A GOP veteran notes that his party did better than expected in 1994 and worse than expected in 1998. Three years ago, Donald Trump was a television personality. Two years ago, he was a long shot for the Republican nomination. One year ago, he moved into the White House. In postmodern, fractured America, nothing is solid. Nothing is certain. And nothing is foreordained.